Exposed printing plate washer

ABSTRACT

An apparatus for washing away water soluble areas of a plastic emulsion covering a plate used in printing operations. Portions of the normally water soluble plastic emulsion become insoluble in water when exposed to ultra violet light through a light dark master. The apparatus consists of a housing wherein circulating heated water is sprayed uniformly over the printing plate by an arrangement of nozzles to remove the portions of the plastic emulsion remaining water soluble. The nozzles uniformly wash all areas of the emulsion coating, developing thereon, in plastic relief, a representation of the light dark master. The housing of the apparatus also contains air jets and heat lamps arranged for drying the developed plate. Exposed printing plates are carried within the apparatus housing by a continuously slowly revolving drum to which an operator releasably mounts each printing plate by spring clamps through an access opening in the housing.

United States Patent [191 Bunker EXPOSED PRINTING PLATE WASHER lnventor:Richard D. Bunker, Salt Lake City,

Utah

Assignee: Dyna-Flex Corporation, Salt Lake City, Utah Filed: Jan. 3,1973 Appl. No.: 214,736

US. Cl ..95/98, 95/93 Int. Cl. ..G03d 3/10 Field of Search ..95/89 R,93, 97,

References Cited UNITED STATES PATENTS Primary Examiner-Samuel S.Matthews Assistant Examiner-Fred L. Braun Attorney-B. Deon Criddle [4 1Apr. 17, 1973 [57] ABSTRACT An apparatus for washing away water solubleareas of a plastic emulsion covering a plate used in printingoperations. Portions of the normally water soluble plastic emulsionbecome insoluble in water when exposed to ultra violet light through alight dark master. The apparatus consists of a housing whereincirculating heated water is sprayed unifon'nly over the printing plateby an arrangement of nozzles to remove the portions of the plasticemulsion remaining water soluble. The nozzles uniformly wash all areasof the emulsion coating, developing thereon, in plastic relief, arepresentation of the light dark master. The housing of the apparatusalso contains air jets and heat lamps arranged for drying the developedplate. Exposed printing plates are carried within the apparatus housingby a continuously slowly revolving drum to which an operator releasablymounts each printing plate by spring clamps through an access opening inthe housing.

5 Claims, 7 Drawing figures 0* {I //a 45 l 43 16 l l 2 I l6 17 2 /7 I Ii //a r I Patented April 17, 1973 3,727,536

3 Sheets-Sheat 1 Patented April 17, 1973 3,727,536

15 Sheets-Sheet 2 Patented April 17, 1973 3 Sheets-Sheet 3 1 EXPOSEDPRINTING PLATE WASHER BRIEF DESCRIPTION OF THE INVENTION continuouslyand completely washing such plates.

SUMMARY OF THE INVENTION It is a principal object of the presentinvention to provide a washing apparatus for removing the water solubleareas of the plastic emulsion covered printing plate of the typedisclosed in my aforesaid application for United States Patent.

Another object is to provide a continuously operating washing apparatuswhose construction allows a number of such printing plates to each beprocessed in turn with only a single operator required to mount activated plates onto a revolving drum of the apparatus and to removewashed plates therefrom.

Another object is to provide a water recycling arrangement within theapparatus wherein water sprayed is caught and reheated as needed forreuse therein.

Still another object is to provide means within the apparatus for theremoval of moisture from the developed plate.

Still another object is to provide a means for easily and releasablysecuring the aforesaid printing plates to the revolving drum of theapparatus.

Principal features of the present invention include a housing wherein anumber of compartments are arranged around a drum revolving therein, oneof said compartments providing an access aperture through the housing tothe drum. Some of the compartments contain nozzles directed towards therevolving drum and uniformly spraying, with temperature controlledwater, a plastic emulsion covered printing plate mounted thereon. Springclamps on the drum are used to releasably position the printing platesas the clamps move past the access aperture. The spray nozzles in eachcompartment are stationary and are arranged in a pattern that willprovide overlapping coverage to uniformly wash the entire face of eachprinting plate moving past the nozzles.

The revolving drum carries each printing plate from the compartmentcontaining the water sprays to a compartment containing apparatus fordrying the washed printing plate. The drying apparatus consists of anumber of air jets and an arrangement of heat lamps all of which aredirected against the revolving drum so as to remove water from therelief surface of a printing plate mounted thereon.

Continued drum revolution passes the washed and dried printing plateback to the access aperture where it is removed before another unwashed,exposed plate is placed thereon.

The heated water sprayed in the apparatus is collected into a storagetank through drains in the housing,

is reheated to the extent necessary to maintain the desired washtemperature, and is recirculated by again pumping it through the spraynozzles.

Brush seals are provided at the sides of the access aperture in theapparatus to allow free rotation of the drum while preventing water andair spray from coming into the access aperture and at a dividerinstalled between washing and drying compartments.

Sets of swivelling spring clamps are mounted to the revolving drum tosecure the corners of the printing plates to the outer wall of the drum.

Additional objects and features of the invention will become apparentfrom the following detailed description and drawings disclosing what ispresently contemplated as being the best mode of the invention.

THE DRAWINGS FIG. 1 is a front elevation view of the continuous printingplate washer of the invention;

FIG. 2, a top plan view;

FIG. 3, a horizontal sectional view taken on the line 33 of FIG. 1;

FIG. 4, a vertical sectional view taken on the line 4- 4 of FIG. 3;

FIG. 5, an enlarged sectional view taken on the line 55 of FIG. 4,showing a typical spring clamp with which a printing plate is releasablyheld to the rotating drum of the invention;

FIG. 6, an enlarged vertical sectional view taken within the line 66 ofFIG. 3, showing a typical water wash nozzle arrangement of theinvention; and

FIG. 7, a horizontal sectional view taken on the line 77 of FIG. 1.

DETAILED DESCRIPTION Referring now to the drawings:

In the illustrated preferred embodiment, the continuous plastic reliefprinting plate washing apparatus is shown generally at 10 and includes ahousing 11 that when viewed from above has a hexagon shape, sup portedby legs 14a of a framework shown generally at 14. A circular drum I2 isarranged to rotate within the housing 11. A motor 13 mounted below thehousing 11, on a beam 14b on frame 14 and is held in place by bolts, notshown, slowly drives drum 12 through a transmission 15 that is alsosupported by beam 14b.

Spray nozzle assemblies 16 are arranged between the inner surfaces ofwalls 11a of housing 11 and the outer wall of drum 12 in a compartment17. Compartment 17 is formed by partitions 17b extending inward fromwalls Ila towards the drum, such that the spray assemblies within thecompartment 17 are separated from an ad joining plate drying chamber andan access aperture. The spray nozzle assemblies 16 are of identicalconstruction so only one will be hereafter described in detail.

Each spray nozzle assembly 16, shown best in FIG. 6, consists of fourupstanding manifold pipes 18 that extend from a common header pipe 18a,in parallel arrangement with one another. Nipples 19 extend from eachpipe 18 towards the drum l2 and a spray nozzle 20 is mounted on the endof each nipple. Each nozzle 20 is mounted to spray water over a definedsegment of a printing plate 21 secured to the drum 12, as will behereinafter described in detail. Each nozzle 20 is mounted to bediagonally offset with respect to its adjacent nozzles so that a uniformspraying occurs at all areas of each printing plate 21.

Water passing through nozzles impinges on drum 12 and on printing plates21 mounted thereon, and then flows from the compartment 17 through acommon drain 22 provided in the compartment bottom 17a. The compartmentbottom 17a is shown inclined towards the drain 22 to insure properdraining. Drain 22 is connected by a line 23 to a reservoir tank 24,mounted below housing 11, on tank supports 25 so as to be supportedwithin the framework 14. Water temperature within tank 24 is maintainedat a desired level by a conventional calrod-type, electrical heatingunit that extends into the tank. As best seen in FIG. 7, a water line 26extends from reservoir 24 to the intake of a pump 27. Water pumpedthrough pump 27 goes through valve 27b and then through a pipe 27c andcommon header pipe 28 into stand pipes 280 to be again forced throughcommon header pipe 180 into upstanding pipes 18 and sprayed from nozzles20. Since the water within the washing apparatus is constantly beingreused only a minimum heat input is required to maintain the water at adesired temperature. An inlet line, not shown, provides make up water totank 24 from a pressure water source, not shown, and a conventionalfloat valve, not shown, within the tank regulates the amount of make upwater admitted.

Drum 12, shown best in FIG. 4, is arranged within housing 11. The drumrests on rollers 29, and is turned through an axle 30 which projectsupwardly from gear box 15 therebelow. The path of revolution of theouter wall of the drum begins at an access aperture 31 through a wall11b of housing 11 and continues through the wash compartment 17, and adrying .chamber 32, before returning to the access aperture 31.

Drying chamber 32, like the chamber 17, is formed in the area providedbetween the inner housing wall 110 and the outer wall of drum 12.Chamber 32 has a partition 17b forming one side wall and anotherpartition 32a forming the other side wall. The bottom 17a is common toall of compartment 17 and chamber 32. While no water is sprayed in thedrying chamber 32, it is desirable to have a drain 22 through bottom 17atherein connected into the drain structures of the wash compartments, sothe water blown from the plates, as will be hereinafter described, willdrain from chamber 32. Chamber 32 contains a system of air jets 33 andan arrangement of infra-red type heat lamps 34 mounted so as to bedirected against the rotating drum l2 and the printing plates 21 mountedthereon. As shown best in FIG. 3, the system of air jets 33 consists of'four distributor tubes 35, each directed towards the drain andconnected to a common air line 36 that extends from the bottom 17a to amidpoint in compartment 32. Each air tube has a number of nozzles 37projecting outward therefrom pointing towards drum 12. Nozzles 37distribute air supplied through the tubes 35 such that it covers allportions of the printing plates 21 as they are moved past the nozzles bydrum 12. Air forced through nozzles 37 thus blows off most of the waterclinging to drum 12 and the passing printing plates 21, and theconventional heat lamps 34, shown best in FIG. 3, further dries awaywater from the plates. The heat lamps are preferably fixed within wall 11c to a reflector 34a that focuses lamp energy in the direction of thedrum. While only one bank of air nozzles and one bank of heat lamps areshown, it should be obvious that more than one bank of each could beused if necessary or desirable.

As shown best in FIGS. 1 and 7, a source of compressed air enters thesystem through a valve 38 mounted on the framework 14, below housing 11and supplies compressed air through an air line 38a and valve 38b to aheater 380 from where heated and compressed air passes through lines 39and 36 to the individual nozzles 37. Electricity is supplied to the bankof heat lamps 34 through a junction box 40 and a thermostat 40a bothlocated beneath the bottom of housing 11. Conventional electricalconduits and switches, not shown, supply electrical energy to operatethe motors and valves as herein described.

The access aperture shown at 31 in housing 11 provides an operatoraccess to the outer wall of the revolving drum 12. Seals 41 and 42,shown in this embodiment as brushes, extend along the opening sides ofthe access aperture to respectively seal the aperture from the adjacentcompartment 17 and chamber 32.

As has been disclosed previously printing plates 21 are releasablysecured to the revolving drum 12 for transport through the washingapparatus. As removal and installation of each plate must beaccomplished while a portion of the drum turns within the accessaperture 31, it is necessary that plate attachment means be providedwhich will hold each plate securely while affording quick securement andeasy rapid removal of the plates.

The holding means shown in FIG. 5, has proven very effective. Theholding means, shown generally at 43, comprises a wire clamp 42comprising a sear or hairpin spring 44 swivel mounted at 44a to theouter wall of the drum 12. One leg 440 of each spring 44 extends throughthe wall of drum 12 and has a loop 44b formed in the end thereof toprevent withdrawal of the leg 44c and the other leg 44d is heldresiliently against the wall of drum 12 by the action of the spring. Theset of clamps includes two clamps spaced and arranged such that the leg44d of each top can be positioned to clamp a corner of a printing plate21 to the drum. A number of sets of clamps are spaced around the drum sothat plates to be processed can be continually placed on the drum andprocessed plates can be removed as the drum rotates.

A defoaming agent contained within a reservoir 45 is pumped by pump 46,as needed, into tank 24 through lines 46a and into tank 24 to eliminatefoam within the tank 24 and the valves in the system.

In operation, the start switch located on junction box 40 is activatedthereby activating motor 13, pump motor 27a, air compressor and heater38c, illuminating heat lamps 34, the water heater unit in the water tank24 and opening water flow valve 27b. Motor 13, through transmission 15,rotates the drum 12 on the bearings 29. An operator clamps a printingplate 21 on the revolving drum by turning wire clamps 43 to position theends of legs 44d on the top corners of the plate. The revolving drum 12carries plate 21 into the chamber 17 where water that has been collectedand heated in tank 24 is forced by liquid pump 27 through spray nozzles20, of each manifold 16, in turn, against the surface of the printingplate. The water sprayed onto the plate 21 dissolves the solubleportions of the emulsion coating thereon, and drains through drains 22and line 23 back to tank 24. As the plate continues to revolve on thedrum, it moves past partition 17!) into drying chamber 32 where theplate 21 on drum 12 is subjected to the high pressure heated air forcedthrough by nozzles 37.-The thermostatic control 40a regulates thetemperature of the air as it is passed through air heater 380. The heatlamps 34 further dry the plate 21. The continuously revolving drum 12then carries plate 21 past brush seal 41 and back into opening 31 wherethe developed plate 21 can be removed from drum l2, and an undevelopedplate 21 can be installed in place thereof. The entire drum peripheralface can be covered by printing plates and as plates are being removedfrom and placed on the drum other plates are being processed. Thus acontinuous plate processing operation can be performed. Alternatively, asingle plate can be processed should this be desired.

Although a preferred form of my invention has been herein disclosed, itis to be understood that the present disclosure is made by way ofexample and that variations are possible without departing from thescope of the hereinafter claimed subject matter, which subject matter Iregard as my invention.

I claim: 1. An exposed plastic relief image printing plate washercomprising a framework; a drum rotatably mounted to said framework;means for revolving said drum; means for releasably mounting an exposedplastic reliefimage printing plate on a portion of said drum; a housinghaving walls surrounding said drum and mounted on said frame; an accessaperture through a wall of the housing exposing a portion of said drum;at least one water spray assembly mounted between said drum and thewalls of said housing, said assembly having spray nozzles arranged touniformly spray said portion of said drum to which an exposed plasticrelief image printing plate is mounted; means for supplying water to thenozzles under pressure; means for collecting and removing sprayed waterfrom said housing; means mounted within said washer between said drumand the walls of said housing for removing water clinging to eachplastic relief image printing plate after it emerges from the waterspray assembly; and divider means within said housing for separatingsaid water spray arrangement from said water removing means and fromsaid access aperture in said housing. 2. An exposed plastic relief imageprinting plate washer as recited in claim 1, wherein the means forreleasably mounting an exposed plastic relief image printing plate on aportion of said revolving drum consists of at least one sear springhaving one leg swivel mounted to said drum, and with the other legthereof resiliently held against the drum. 3. An exposed plastic reliefimage printing plate washer as recited in claim 1, wherein the means forremoving clinging water from the plastic relief image printing platecomprises an assembly of airjets mounted so as to direct air from acompressed air source against the surface of the drum mounted plasticrelief image printing plate. 4. An exposed plastic relief image printingplate washer as recited in claim 3, further including means to heat thecompressed air.

5. An exposed plastic relief image printing plate washer as recited inclaim 4, wherein the means for removing clinging water from the plasticrelief image printing plate further includes an arrangement of heatlamps mounted to radiate against each printing plate.

1. An exposed plastic relief image printing plate washer comprising aframework; a drum rotatably mounted to said framework; means forrevolving said drum; means for releasably mounting an exposed plasticrelief image printing plate on a portion of said drum; a housing havingwalls surrounding said drum and mounted on said frame; an accessaperture through a wall of the housing exposing a portion of said drum;at least one water spray assembly mounted between said drum and thewalls of said housing, said assembly having spray nozzles arranged touniformly spray said portion of said drum to which an exposed plasticrelief image printing plate is mounted; means for supplying water to thenozzles under pressure; means for collecting and removing sprayed waterfrom said housing; means mounted within said washer between said drumand the walls of said housing for removing water clinging to eachplastic relief image printing plate after it emerges from the waterspray assembly; and divider means within said housing for separatingsaid water spray arrangement from said water removing means and fromsaid access aperture in said housing.
 2. An exposed plastic relief imageprinting plate washer as recited in claim 1, wherein the means forreleasably mounting an exposed plastic relief image printing plate on aportion of said revolving drum consists of at least one sear springhaving one leg swivel mounted to said drum, and with the other legthereof resiliently held against the drum.
 3. An exposed plastic reliefimage printing plate washer as recited in claim 1, wherein the means forremoving clinging water from the plastic relief image printing platecomprises an assembly of air jets mounted so as to direct air from acompressed air source against the surface of the drum mounted plasticrelief image printing plate.
 4. An exposed plastic relief image printingplate washer as recited in claim 3, further including means to heat thecompressed air.
 5. An exposed plastic relief image printing plate washeras recited in claim 4, wherein the means for removing clinging waterfrom the plastic relief image printing plate further includes anarrangement of heat lamps mounted to radiate against each printingplate.